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UNITED STATES DEPARTMENT OF AGRICULTURE 

BULLETIN No. 613 

Contribution from the States Relations Service 

A. C. TRUE, Director J&$ < &3 : U 





Washington, D. C. 



PROFESSIONAL PAPER 



April 25, 1919 



DIGESTIBILITY OF CERTAIN MISCELLANEOUS 

ANIMAL FATS. 1 

By Aethur D. Holmes, Specialist in Charge of Digestion Experiments, Office 

of Home Economics. 



CONTENTS. 

Page. 



Introduction 

Methods of procedure. 

Subjects 

Goat's butter 

Kid fat 

Hard-palate fat 

Horse fat 



1 

2 
3 
3 
6 
8 
10 



Oleo oil 

Oleo stearin . . . 
Ox-marrow fat . 

Ox-tail fat 

Turtle fat 

Summary 



12 
15 
17 
19 
22 
24 



INTRODUCTION. 

Earlier papers 2 of this series have reported the coefficients of 
digestibility of lard, beef and mutton fats, and butter; cream, 
chicken, goose, egg-yolk, brisket and fish fats; olive, cottonseed, 
peanut, coconut and sesame oils and cocoa butter; almond, black- 
walnut, Brazil nut, butternut, English walnut, hickory nut, and 
pecan oils; corn, soy-bean, sunflower-seed, Japanese mustard-seed, 
rapeseed and charlock-seed oils. The present paper deals with the 
digestibility of goat's butter, kid fat, hard-palate fat, horse fat, oleo 
oil, oleo stearin, ox-marrow, ox-tail, and turtle fats. Though oleo oil 
and oleo stearin are of much importance commercially, the fats dis- 
cussed in this bulletin, as a whole, are not commonly known in 
American homes. However, they are, for one reason or another, of 
interest in considering culinary and table fats as well as in the con- 
sideration of general problems related to the use of fats as food. A 
few of these fats were purchased in the open market and the re- 
mainder were secured through the cooperation of Government and 
commercial activities. The hard-palate, horse, kid, and turtle fats 
were rendered in the laboratory by cutting the unrendered fat very 
fine, heating in a double boiler until the fat was completely melted, 
and then straining through rather thick cloth. The oleo oil, oleo 

1 Prepared under the direction of C. F. Langworthy, Chief, Office of Home Economics. 
8 See list of bulletins on page 26. 

95191°— 19— Bull. 613 1 



.-. 









^ 



2 BULLETIN 613, U. S. DEPARTMENT OF AGRICULTURE. 

stearin, ox -marrow, and ox-tail fats were obtained already rendered 
from commercial concerns. In order to insure uniform composition 
a sufficient quantity of each of the fate for the purpose of the study 
was thoroughly mixed before it was incorporated in the blancmange, 
which served as a medium for supplying the fat to the diet. 

METHODS OF PROCEDURE. 

The regimen followed was the same as that in previous experi- 
ments, foods containing a minimum amount of fat being chosen as a 
basal diet, i. e., wheat biscuits, oranges, and sugar. The fat to be 
studied was incorporated in a cornstarch pudding, a caramel solution 
being added to conceal any pronounced flavor. A sufficient amount of 
this pudding was prepared for the entire experiment. It was de- 
sired that such quantities as were necessary to provide about 100 
grams of fat should be eaten by each subject daily, this amount be- 
ing approximately one-third the total energy of the diet which is the 
average proportion furnished by fat. Coffee and tea, without cream, 
were permitted according to individual preference. The experimen- 
tal diet was eaten for three days or nine meals in each case. This 
period has been found satisfactory in the previous tests as it is 
sufficient to give satisfactory results and not so long as to introduce 
any undesirable physiological effect due to monotony. A 4-days 
period of normal diet was always followed before beginning a 
new test. 

For separation of the feces from this diet, charcoal was adminis- 
tered in gelatin capsules with the first meal on the fat-containing 
diet, and with the first meal on resuming the customary diet. The 
feces were collected in weighed-glass containers, weighed, and then 
dried in an electric oven at 95° C., pulverized and analyzed. No urine 
analyses were made and no effort to maintain a nitrogen equilibrium, 
the digestibility of the fats being the special object of investigation. 
The coefficients of digestibility of the protein, fat, and carbohydrate 
supplied by the diet as a whole were determined directly. From 
these data the digestibility of the fat under consideration was esti- 
mated by the method commonly followed and outlined in detail in 
a previous bulletin. 1 In computing the figure for digestibility of the 
fat alone, in each experiment correction was made for metabolic 
products and the small amount of undigested basal ration fat which 
occurs in the ether extract of the feces. 

In general it has been the practice during the study of the digesti- 
bility of the edible fats to conduct not less than Rye tests of three 
days' duration each. Since the available supply of fat in the case of 
a number of fats here studied was small, as few as three experi- 
ments were made in some instances. 

X U. S. Dept. Agr. Bui. 310 (1915), pp. 22. 



Wo 

MAY 



of. L>. 



DIGESTIBILITY OF MISCELLANEOUS ANIMAL FATS. 3 

SUBJECTS. 

The subjects were all men who had previously served in the same 
sftry capacity. They were between 20 and 40 years of age, in good health, 
and took a moderate amount of exercise. They observed regular 
hours for meals and followed their normal daily occupations. Since 
the subjects were students, they would be classed properly as persons 
engaged in light muscular activities. All were in good physical con- 
dition, possessing healthy appetites and normal digestive functions. 

GOAT'S BUTTER. 

Goat's milk, butter, and cheese have long been common foods in 
many localities in Europe, yet, aside from chemical analyses, seem to 
have been little studied. It has long been believed that goat's milk is 
in some way superior to cow's milk for infant f eedmg. This belief is 
probably based on the result of empirical observations for the data 
found in the literature does not unif ormly substantiate such a belief. 
To obtain more complete data on the relative nutritive values of 
goat's and cow's milk, Sherman and Lohnes 1 made a comparative 
study of the two with infants and found that the curds of goat's 
milk were smaller and more flocculent than those of cow's milk, that 
goat's milk has finer fat globules and exhibits more thorough emulsifi- 
cation of the fat ; that cow's milk has greater stimulating effect on the 
stomach; that in 16 cases, 12 babies gained more rapidly on cow's 
milk and 4 more rapidly on goat's milk; that 5 vomited on goat's 
milk and none on cow's milk; and that children taking goat's milk 
cried more at night. Bosworth and Van Slyke, 2 who have studied 
the nature of the casein 3 and soluble and insoluble compounds of 
goat's milk 4 and compared the composition of cow's, goat's, and 
human milk, 5 report that goat's milk 6 is less acid, contains a larger 
amount of chlorids, and that the phosphates are combined with more 
bases than in cow's milk. Jordan and Smith 6 have made extensive 
analyses of goat's milk. They concluded that there was no essential 
difference between the casein, but that there were marked differences 
in the nature of the ash obtained from cow's and goat's milk. Hall 7 
states that goat's milk is palatable, nutritious, easily digested, helpful 
in certain cases of poor nutrition, and practically free from liability 
to transmit diseases like tuberculosis. 

Very recently Hill 8 has reported a series of chemical analyses of 
milk produced by a four-months-old virgin doe kid, and states: " The 

1 Jour. Amer. Med. Assoc, 62 (1914), No. 23, pp. 1806, 1807. 

2 X. Y. State Agr. Expt. Sta. Tech. Bui., 46 (1915), p. 3. 

8 Jour. Biol. Chem., 24 (1916), No. 3, pp. 173-175. 

*Jour. Biol. Chem., 24 (1916), Xo. 3, pp. 177-185. 

5 Jour. Biol. Chem., 24 (1916), Xo. 3, pp. 187-189. 

6 N. Y. State Agr. Expt. Sta. Bui., 429 (1917), p. 4. 

7 N. Y. State Agr. Expt. Sta. Bui., 429 (1917), pop. ed., p. 7. 

8 Jour. Biol. Chem., 33 (1918), Xo. 3, p. 392. 



4 BULLETIN 613, U. S. DEPARTMENT OE AGRICULTURE. 

milk was substituted in the diet of an 11 -months-old baby for normal 
goat's milk without any detectable difference either in the appetite 
or physical condition of the baby." 

The literature consulted gave no information as to the presence or 
absence in goat's milk and butter of the fat-soluble vitamin con- 
tained in cow's butter. In view of the use of goat's milk for in- 
fant feeding, information on this point would be of especial im- 
portance, since goat's milk is in many parts of the world the com- 
mon household milk supply. 

A supply of goat's butter sufficient for the purpose of these ex- 
periments was obtained from the Dairy Division of the Bureau of 
Animal Industry. The butter was of a very pale-yellow color, 
without pronounced odor or flavor, and by those not informed of 
its nature it was«taken for light-colored dairy butter. Since only a 
limited supply was available, no tests were made regarding its use in 
cookery, and the entire sample was incorporated in the usual corn- 
starch blancmange. 

Four experiments were conducted to determine the digestibility of 
goat's butter and the data which resulted are recorded in the follow- 
ing tables : 
Data of digestion experiments with goafs-milk butter in a simple mixed diet. 





Weight 
of foods. 


Constituents of foods. 


Experiments, subjects, and diet. 


Water. 


Protein. 


Fat. 


Carbohy- 
drate. 


Ash. 


Experiment No. 645, subject A. F. 

Blancmange containing goat's milk butter. 
Wbeat biscuit 


Grams. 

2,086.0 
245.0 
829.0 
152.0 


Grams. 

1,176.4 

22.0 

720.4 


Grams. 

54.8 

26.0 

6.6 


Grams, 

144.1 

3.7 

1.7 


Grams. 

699.0 

189.4 

96.2 

152.0 


Grams. 

11.7 

3 9 


Fruit 


4.1 


Sugar 












Total food consumed 


3,312.0 
76.0 


1,918.8 


87.4 
24.8 
62.6 


149.5 
11.3 

138.2 


1,136.6 
31.9 

1,104.7 


19.7 


Feces 


8.0 


Amount utilized 




11.7 










Per cent utilized 






71.6 


92.4 


97.2 


59.4 










Experiment No. 646, subject P. K.: 

Blancmange containing goat's milk butter. 
Wheat biscuit 


1,809.0 
248.0 
502.0 
191.0 


1,020.3 

22.3 

436.3 


47.4 

26.3 

4.0 


125.0 
3.7 
1.0 


606.2 

191.7 

58.2 

191.0 


10.1 
4.0 


Fruit 


2.5 


Sugar 














Total food consumed 


2, 750. 
51.0 


1,478.9 


77.7 
18.0 
59.7 


129.7 

8.1 

121.6 


1,047.1 

20.2 

1,026.9 


16 6 


Feces 


4 7 


Amount utilized 




11 9 










Per cent utilized 






76.8 


93.8 


98.1 


71 T 










Experiment No. 647, subject J. C. M.: 

Blancmange containing goat's milk butter. 
Wheat biscuit 


1,775.0 
316.0 
384.0 
175.0 


1,001.1 

28.4 

333.7 


46.6 

33.5 

3.1 


122.6 

4.7 

.8 


594.8 

244.3 

44.5 

175.0 


9.9 
5 1 


Fruit 


1 9 
















Total food consumed 


2, 650. 
70.0 


1,363.2 


83.2 
23.0 
60.2 


128.1 

8.6 

119.5 


1,058.6 

32.4 

1,026.2 


16.9 


Feces 


6.0 


Amount utilized 




10.9 












Per cent utilized 






72.4 


93.3 


96.9 


GL5 











DIGESTIBILITY OF MISCELLANEOUS ANIMAL FATS. 



Data of digestion experiments with goafs-milk butter in a simple mixed 

diet — Continued. 





Weight 
of foods. 


Constituents of foods. 


Experiments, subjects, and diet. 


Water. 


Protein. 


Fat. 


Carbohy- 
drate. 


Ash. 


Experiment No. 648, subject A. A. R.: 

Blancmange containing goat's milk butter. 


Grams. 
1,770.0 

192.0 
1,059.0 

210.0 


Grams. 

998.3 

17.3 

920.3 


Grams. 

46.4 

20.3 

8.5 


Grams. 

122.3 

2.9 

2.1 


Grams. 
593.1 
148.4 
122.8 
210.0 


Grams. 
9.9 
31 


Fruit 


5.3 
















Total food consumed 


3,231.0 
71.0 


1,935.9 


75.2 
25.0 
50.2 


127.3 

6.6 

120.7 


1,074.3 

33.0 

1,041.3 


18.3 




6.4 






11.9 
















66.8 


94.8 


96.9 


65.0 










Average food consumed per subject per day. . . 


995.3 


558.1 


27.0 


44.6 


359.7 


6.0 



Summary of digestion experiments with goafs-milk, butter in a simple mixed 

diet. 





Experiment No. 


Subject. 


Digestibility of entire ration. 


Esti- 
mated 




Protein. 


Fat. 


Carbohy- 
drate. 


Ash. 


digesti- 
bility of 
goat's 
milk but- 
ter alone. 


645 


A. F 


Per cent. 
71.6 
76.9 
72.4 
66.8 


Per cent. 
92.4 
93.8 
93.3 
94.8 


Per cent. 
97.2 
98.1 
96.9 
96.9 


Per cent. 
59.4 
71.7 
64.5 
65.0 


Per cent. 
97.4 


646 


P. K 


97.5 


647 


J. C. M . 


98.6 


648 


A. A. R 


100.0 




Average 








71.9 


93.6 


97.3 


65.2 


98.4 











Considering the diet as a whole, the subjects ate on an average 
27 grams of protein, 45 grams of fat, and 360 grams of carbohydrate 
daily, which supplied approximately 2,079 calories of energy. Since 
the available amount of goat's butter was small, only about 45 grams 
of fat, of which about 43 grams was goat's butter, was eaten daily. 

The digestibility was found to be 71.9 per cent for protein, 93.6 
per cent for fat, and 97.3 per cent for the carbohydrate supplied by 
the diet as a whole. When correction is made for the metabolic 
products and undigested basal-ration fat which occurs in the ether 
extract of the feces, the figure 93.6 per cent for the digestibility of 
the total fat of the diet becomes 98.4 per cent for the digestibility of 
goat's butter alone. 

For the sake of comparison it is of interest in this connection to 
refer to the figure for the digestibility of cow's butter 1 determined 
under conditions identical with those maintained for the experiments 
here reported. This was found to be 97 per cent, a difference, which 
for all practical dietetic purposes is negligible as compared with 99 

*U. S. Dept. Agr. Bui. 310 (1915), p. 21. 



6 



BULLETIN 613, U. S. DEPARTMENT OF AGRICULTURE. 



per cent, the digestibility of goat's butter. Since all the subjects re- 
ported that they were in normal physical condition during the entire 
period of these experiments, it appears that goat's butter is a whole- 
some valuable food fat. 

KID FAT. 

The consumption of kid fat is quite limited in this country, being 
confined largely to those of foreign birth and food habits, who in- 
clude goat or kid meat in their dietary. Just as the consumption of 
lamb greatly exceeds that of mutton, the amount of kid meat eaten 
exceeds that of goat meat. Kid fat has little if any sale in this 
country as an edible fat; however, it seemed of interest to compare 
its digestibility with that of mutton fat. 

Through the courtesy of the Bureau of -Animal Industry, one-half 
of the carcass of a 6-months-old kid was secured for experimental 
purposes. The kidney fat and all of the superficial fat was carefully 
removed, finely cut, and rendered in a double boiler. The meat was 
cooked and its digestibility determined by means of the usual diges- 
tion experiments, the results of which are reserved for future dis- 
cussion. The fat which cooked out of the meat was carefully saved 
and, since it had not been scorched and was free from any suspended 
matter, was added to the rendered kidney fat in order that a suffi- 
cient quantity of fat should be available for the experiments reported 
below. 



Data of digestion experiments with kid fat in a simple mixed diet: 





Weight 
of foods. 


Constituents of foods. 


Experiments, subjects, and diet. 


Water. 


Protein. 


Fat. 


Carbohy- 
drate. 


Ash. 


Experiment No. 712, subject P. K.: 

Blancmange containing kid fat 


Grams. 

1, 506. 
319.0 
492.0 
197.0 


Grams. 
813.1 

28.7 
427.5 


Grams. 

27.7 

33.8 

3.9 


Grams. 

177. 

4.8 

1.0 


Grams. 

476.5 

246.6 

57.1 

197.0 


Grams, 

11.7 

5.1 

2 5 


Wheat biscuit 


Fruit 


Sugar 














Total food consumed 


2,514.0 
72.0 


1, 269. 3 


65.4 
7.0 

58.4 


182.8 

16.5 

166.3 


977.2 

41.9 

935.3 


19.3 

6.6 

12.7 


Feces 


Amount utilized 










Per cent utilized 






89.3 


91.0 


95.7 


65.8 








Experiment No. 713, subject J. C M.: 

Blancmange containing kid fat 


1,641.0 
388.0 

1,013.0 
149.0 


886.0 

34.9 

880.3 


30.2 

41.2 

8.1 


192.8 
5.8 
2.0 


519.2 
299.9 
117.5 
149.0 


12.8 
6.2 
5.1 


Wheat biscuit 


Fruit 














Total food consumed 


3, 191. 
69.0 


1,801.2 


79.5 
2.3 

77.2 


200.6 

9.7 

190.0 


1, 085. 6 

50.9 

1, 034. 7 


24.1 

6.1 

18.0 


Feces 


















97.1 


95.2 


95.3 


" 74~7 







DIGESTIBILITY OF MISCELLANEOUS ANIMAL FATS. 7 

Data of digestion experiments with kid fat in a simple mixed diet — Continued. 



Experiments, subjects, and diet. 



Constituents of foods. 



Weight 
of foods. 



Water. 



Protein. 



Fat. 



Carbohy- 
drate. 



Ash. 



Experiment No. 714, subject A. A. R.: 

Blancmange containing kid fat 

Wheat biscuit 

Fruit 

Sugar 



Grams. 
1, 428. 

237.0 
1, 204. 

168.0 



Grams. 

771.0 

21.3 

1, 046. 3 



Grams. 

26.3 

25.1 

9.6 



Grams. 

167.8 

3.6 

2.4 



Grams. 
451.8 
183.2 
139.7 
168.0 



Grams. 

11.1 

3.8 

6.0 



Total food consumed . 

Feces 

Amount utilized 



3, 037. 
104.0 



1,838.6 



61.0 
13.1 
47.9 



173.8 

21.4 

152.4 



942.7 

59.4 

883.3 



20.9 
10.1 
10.8 



Per cent utilized m '. 



78.5 



87.7 



93.7 



51.7 



Average food consumed per subject per day — 



971.3 



945.5 



22.9 



61.9 



333.9 



7.1 



Summary of digestion experiments ivith kid fat in a simple mixed diet. 





Experiment No. 


Subject. 


Digestibility of entire ration. 


Estima- 
ted Al- 

gestfbil- 
ityof 
kid fat 
alone. 




Protein. 


Fat. 


Carbohy- 
drate. 


Ash. 


712 


P. K 


Per cent. 
89.3 
97.1 

78.5 


Percent. 
91.0 
95.2 
87.7 


Per cent. 
95.7 
95.3 
93.7 


Per cent. 
65.8 
74.7 
51.7 


Per cent. 
94.1 


713 


J. C. M 


98.4 


714 


A. A. R 


93.4 




Average 








88.3 


91.3 


94.9 


64.1 


95.3 











The coefficients of digestibility of the diet as a whole were found to 
be 88.3 per cent for protein, 91.3 per cent for fat, 94.9 per cent for 
carbohydrate, and the estimated digestibility of kid fat alone is 95.3 
per cent. This figure obtained for the digestibility of kid fat is per- 
haps not directly comparable with the coefficient of digestibility, 88 
per cent, previously reported 1 for mutton fat, since the mutton fat 
was kidney fat and the kid fat was a mixed fat obtained from all 
parts of the carcass, and as has been previously noted, 2 the nature of 
fat varies somewhat with the part of the body from which it is taken. 
Though a little lower it compares very favorably in digestibility with 
goat's butter which was 99 per cent digested. The average amount 
of kid fat eaten daily, 62 grams, was somewhat in excess of 53 grams, 
the average daily consumption of mutton fat. 

In the reports of their physical condition during the test period, 
none of the subjects made any mention of any laxative effect or other 
digestive disturbances resulting from the experimental diet, and 
accordingly on the basis of the experiments here reported, it may be 
assumed that kid fat, when eaten in amounts not in excess of 60 



!U. S. Dept. Agr. Bui. 310 (1015), p. 21. 
2 U. S. Dept. Agr. Bui. 507 (1917), p. 9. 



8 BULLETIN 613, U. S. DEPARTMENT OF AGRICULTURE. 

grams daily is quite well assimilated and is suited for use as human 
food. 

HARD-PALATE FAT. 

The so-called " hard palates " are taken from the roof of the mouth 
of beef animals. In appearance they are very unattractive, pos- 
sessing a black or white, rough, ribbed outer surface, and contain 
little muscular tissue. According to information obtained from the 
Bureau of Animal Industry, 1 several of the large packing establish- 
ments utilize the hard palates of cattle in the preparation of edible 
products, such as potted meats, sausage, etc. One establishment is 
reported as saying about 2,500 pounds monthly, another about 6,000 
pounds monthly. In view of this rather extensive use of hard palates 
for food purposes, it appeared very desirable to ascertain the digesti- 
bility of this material, and accordingly seven experiments were con- 
ducted in this laboratory, and it was found that the protein was ap- 
proximately 87 per cent digested. 2 Some attention was paid also to 
the fat of the hard palates, and its possible uses for culinary purposes 
emphasized the desirability of studying its digestibility. 

In the preparation of the hard palates for use in the experiments 
referred to they were boiled for two to three hours, a yellow fat 
being extracted during the process. While hard palates contain 
only a small amount of this fat — about 11 per cent — of which ap- 
proximately one^half is extracted by boiling the hard palates for 
two or three hours, the total yield of packing houses preparing two 
or three tons per month of hard palates for edible purposes is evi- 
dently of commercial importance. 

The hard-palate fat used in this study was obtained by boiling 
palates for two or three hours in a large amount of water. About 
100 pounds of fresh hard palates secured from a local abattoir were 
extracted in this manner. The fat, which floated to the top of the 
liquor, hardened on cooling and was removed and purified by re- 
melting several times in boiling water. It had a yellow color, was 
without characteristic taste, and resembled butter somewhat in ap- 
pearance, though it was more granular. 

As previously reported, 3 it was found to have a melting point of 
34° C, an iodin number of 52.53, and a refractive index of 1.45&6. 

Three subjects assisted in the study of this fat. The results of 
the tests are reported in the following tables : 

1 Personal communication. 

2 Digestibility of Hard Palates of Cattle, Jour. Agr. Research, 6 (1916), No. 17. 
3 Loc. cit. 



DIGESTIBILITY OF MISCELLANEOUS ANIMAL FATS. 9 

Data of digestion experiments ivith hard-palate fat in a simple mixed diet. 





Weight 
of foods. 


Constituents of foods. 


Experiments, subjects, and diet. 


Water. 


Protein. 


Fat. 


Carbohy- 
drate. 


Ash 


Experiment No. 574. subject A. J. H.: 

Blancmange containing hard -palate fat 


Grams. 
1,329.0 

87.0 
305.0 

65.0 


Grams. 

522.8 

7.8 

265.1 


Grams. 

24.1 

9.2 

2.4 


Grams. 

201.7 

1.3 

0.6 


Grams. 

569.1 

67.3 

35.4 

65.0 


Grams. 

11.3 

1.4 


Fruit 


1.5 
















Total food consumed 


1, 786. 
75.0 


795.7 


35.7 
25.7 
10.0 


203.6 

22.8 

180.8 


736.8 

18.8 

718.0 


14.2 


Feces.. - • 


7.7 






6.5 
















28.0 


88.8 


97.4 


45.8 










Experiment No. 575, subject P. K.: 

Blancmange containing hard-palate fat 

Wheat biscuit 


1,924.0 

357.0 

861.0 

69.0 


756. 9 
32.1 

748.2 


34.8 

37.8 

6.9 


292.1 
5.4 
1.7 


823.9 

276.0 

99.9 

69.0 


16.3 
5.7 


Fruit 


4.3 


Sugar 














Total food consumed 


3,211.0 
82.0 


1,537.2 


79.5 
26.0 
53.5 


299.2 

27.2 

272.0 


1, 268. 8 

20.2 

1,248.6 


26.3 


Feces 


8.6 


Amount utilized 




17.7 










Per cent utilized 






67.3 


90.9 


98.4 


67.3 










Experiment No. 576, subject C. J. W.: 

Blancmange containing hard-palate fat 

"Wheat biscuit. 


1,949.0 

341.0 

1,011.0 

81.0 


766.7 
30.7 

878.6 


35.3 

36.1 
8.1 


295.9 
5.1 
2.0 


834.5 

263.6 

117.3 

81.0 


16.6 
5.5 


Fruit 


5.0 


Sugar 














Total food consumed 


3,382.0 
110.0 


1, 676. 


79.5 
33.9 
45.6 


303.0 
25.2 

277.8 


1, 296. 4 

37.1 

1,259.3 


27.1 


Feces 


13.8 


Amount utilized 




13.3 










Per cent utilized 






57.4 


91.7 


97.1 


49.1 










Average food consumed per subject per day 


931.0 


445.5 


21.6 


89.5 


366.9 


7.5 



Summary of digestion experiments with hard-palate fat in a simple mixed diet. 





Experiment No. 


Subject. 


Digestibility of entire ration. 


Esti- 
mated di- 




Protein. 


Fat. 


Carbohy- 
drate. 


Ash. 


gestibil- 
ity of 

hard-pal- 
ate fat 
alone. 


574 


A. J. H 


Per cent. 
28.0 
67.3 
57.4 


Per cent. 
88.8 
90.9 
91.7 


Per cent. 
97.4 
98.4 
97.1 


Per cent. 
45.8 
67.3 
49.1 


Per cent. 
95 4 


575 


P. K. 


93 5 


576 


C. J. W. 


95 2 




Average 








50.9 


90.5 


97.6 


54.1 


93 7 











It will be noted on referring to the above tables that the subjects 
ate on an average 22 grams of protein, 90 grams of fat, and 367 grams 
of carbohydrate daily, which had a fuel value of 2,366 calories. The 
protein, fat, and carbohydrate supplied by the total diet were 50.9 
per cent, 90.5 per cent, and 97.6 per cent digested, respectively. When 
corrections are made for the metabolic products and undigested fat 
resulting from the basal ration occurring in the feces the value, 90.5 
95191°— 19— Bull. 613 2 



10 BULLETIN 613, U. S. DEPARTMENT OF AGRICULTURE. 

per cent, for the digestibility of the total fat of the diet becomes 93.7 
per cent for the digestibility of the hard-palate fat. 

The subjects all reported that they were in normal physical condi- 
tion during the period of these experiments, and accordingly it ap- 
pears that hard-palate fat of good quality may be eaten as a con- 
stituent of a simple mixed diet at least in amounts not exceeding 90 
grams daily without physiological disturbances. 

HORSE FAT. 

At present horse flesh is sold for human food in this country in 
only a few of the larger cities. That the supply of animals exceeds 
the demand 1 is shown by letters received by commission firms in 
Chicago from Montana ranchmen offering in carload lots animals 
that were " overaged," " wire cut," " undersized," and " inbred," but 
in " good flesh and health." Horse flesh is quite generally used for 
human food in some European countries, for it is reported 2 that 
as long ago as 1892 in Paris and Vienna over 20,000 horses were 
slaughtered for human food. " Similar statistics are furnished also 
from Berlin and other public abattoirs in Prussia, and the supply 
of horse flesh as a meat food for the public has become a regular and 
well-organized business." In 1910, 29,000,000 pounds of horse meat 3 
was produced for consumption in Paris and its environs. In Ger- 
many, in 1909, 152,214 horses were slaughtered, which provided 
79,000,000 pounds of meat ; approximately 1J pounds per capita. 

It is apparent from these statements that horse fat as a part of the 
meat enters into the European dietary. It is evidently also known as 
a separated fat, for Lewkowitsch 4 reports that " it is used by the 
poorer classes on the Continent as an edible fat in the place of lard, 
and is no doubt used as an adulterant of more expensive fats." There 
is a tradition in some foreign countries that it has a special value 
as shortening in pastry making. 

Though no definite information regarding its use for such purposes 
in the United States has been found, it seemed not without interest 
to include a study of horse fat, and in order that the results obtained 
might be directly comparable with those obtained for beef, mutton, 
and pork (kidney fats), reported in an earlier paper, 5 an attempt was 
made to secure a supply of horse-kidney fat. However, after several 
horses had been slaughtered without securing from any sufficient 
kidney fat for the purpose of this study, it was decided to study a 

iNat. Provisioned 58 (1918), No. 16, p. 17. 
2 Lancet [London], 1 (1918), No. 5, p. 189. 

8 Jour. Amer. Vet. Med. Assoc, n. ser., 4 (1917), No. 5, p. 681. 

* Chemical Technology and Analysis of Oils, Fats, and Waxes, II. J. Lewkowitsch, 
London: Macmillan and Co. (1909), j. 547. 
5 U. S. Dept. Agr. Bui. 310 (1915). 



DIGESTIBILITY OF MISCELLANEOUS ANIMAL FATS. 



11 



composite fat taken from different parts of the body. Through the 
courtesy of Superintendent Hollister, of the National Zoological 
Park, a supply of horse fat (neck and leaf) was secured from a 
healthy inspected animal, such as are regularly procured to supply 
food for the carnivorous animals confined in the park. In the un- 
rendered form its physical appearance was so similar to that of beef 
fat that the members of the laboratory staff who were unaware of its 
source assumed it to be beef fat. Samples of the neck and leaf fats 
which were analyzed by R. H. Kerr, of the Bureau of Animal In- 
dustry, were found to have the following constants : Neck fat, iodin 
number 95.83 and refractive index at 40° C. 55.5° and leaf fat, iodin 
number 91.22 and refractive index at 40° C. 54.0°. The unrendered 
fats were passed through a meat cutter, uniformly mixed, and ren- 
dered in a double boiler. The rendered fat on standing tended to 
separate into an oily and solid layer, resembling chicken fat in this 
respect. 

Three subjects assisted in the experiments, which are reported in 
the tables which follow : 



Data of digestion experiments with horse fat in a simple mixed diet. 





Weight 
of foods. 


Constituents of foods. 


Experiments, subjects, and diet. 


Water. 


Protein. 


Fat. 


Carbohy- 
drate. 


Ash. 


Experiment No. 747, subject P. K.: 

Blancmange containing horse fat 


Grams. 

1,634.0 
304.0 
514.0 
265.0 


Grams. 

734.2 

27.4 

446.7 


Grams. 

33.0 

32.2 

4.1 


Grams. 

184.0 

4.5 

1.0 


Grams. 

669.1 

235.0 

59.6 

265.0 


Grams. 
13.7 


Wheat biscuit 


4.9 


Fruit 


2.6 


Sugar 














Total food consumed 


2,717.0 
67.0 


1,208.3 


69.3 
22.3 

47.0 


189.5 

9.4 

180.1 


1,228.7 

29.9 

1,198.8 


21.2 


Feces 


5.4 


Amount utilized 




15.8 










Per cent utilized 






67.8 


95.0 


97.6 


74.5 










Experiment No. 748, subject M. L. M.: 

Blancmange containing horse fat 


1,670.0 
558.0 
667.0 
429.0 


750.3 

50.2 

579.6 


33.7 

59.2 

5.4 


188.1 
8.4 
1.3 


683.9 
431.3 

77.4 
429.0 


14.0 


Wheat biscuit 


8.9 


Fruit 


3.3 


Sugar 














Total food consumed 


3,324.0 
133.0 


1,380.1 


98.3 
40.8 
57.5 


197.8 

13.2 

184.6 


1,621.6 

68.3 

1,553.3 


26.2 


Feces 


10.7 


Amount utilized 




15. 5 










Per cent utilized 






58.5 


93.3 


95.8 


59.2 










Experiment No. 749, subject J. C M.: 

Blancmange containing horse fat 


1,719.0 
385.0 
948.0 
194.0 


772.4 

34.6 

823.8 


34.7 

40.8 

7.6 


193.6 
5.8 
1.9 


703.9 
297.6 
110.0 
194.0 


14.4 


Wheat biscuit 


6.2 


Fruit 


4.7 


Sugar 














Total food consumed 


3,246.0 
123.0 


1,630.8 


83.1 
37.4 
45.7 


201.3 

15.3 

186.0 


1,305.5 

59.8 

1,245.7 


25.3 


Feces 


10.5 


Amount 




14.8 










Per cent utilized 






55.0 


92.4 


95.4 


58.5 










Average food consumed per subject per day . . . 


1,032.0 


468.8 


27.9 


65.4 


461.8 


8.1 



12 BULLETIN 613, U. S. DEPARTMENT OF AGRICULTURE. 

Summary of digestion experiments with horse fat in a simple mixed diet. 





Experiment No. 


Subject. 


Digestibility of entire ration. 


Esti- 
mated 




Protein. 


Fat. 


Carbohy- 
drate. 


Ash. 


digesti- 
bility of 
horse fat 
alone. 


747 


P. K 


Per cent. 
67.8 
58.5 
55.0 


Percent, 
95.0 
93.3 
92.4 


Per cent. 
97.6 
95.8 
95.4 


Per cent. 
74.5 
59.2 

58.5 


Per cent. 
95.2 


748 


M. L. M 


93.7 


749 


J. CM 


92.7 




Average 








60.4 


93.6 


96.3 


64.1 


93.9 











The fat-rich blancmange containing horse fat formed the predomi- 
nating part of a simple mixed diet and was eaten without comment, 
indicating that this blancmange was as acceptable as that served in 
other experiments of a similar nature. All the subjects stated, in the 
reports which they submitted regarding their physical condition dur- 
ing the experimental period, that they continued in normal health. 

On an average the subjects ate 28 grams of protein, 65 grams of 
fat, and 462 grams of carbohydrate daily, which supplied 2,545 calo- 
ries of energy. The coefficients of digestibility of the diet as a whole 
were for protein 60.4 per cent, for fat, 93.6 per cent, and for the 
carbohydrate 96.3 per cent. If correction for the metabolic products 
and undigested basal ration fat is applied to the figure 93.6 per cent, 
the digestibility of the total fat of the diet, it is found that the coeffi- 
cient of digestibility of horse fat alone is 93.9 per cent. This figure, 
93.9 per cent, is for dietetic purposes the same as 93 per cent re- 
ported 1 in an earlier paper for the digestibility of beef -kidney fat. 
It is higher than the digestibility reported from similar experiments 
with mutton-kidney fat 1 (88 per cent) , and somewhat lower than the 
digestibility of lard 1 (97 per cent), butter 1 (97 per cent), and beef- 
brisket fat 2 (97.4 per cent). 

On the basis of these experiments it appears that rendered horse 
fat obtained from healthy animals when eaten as a part of a simple 
mixed diet in amounts not exceeding 65 grams daily produces no 
physiological disturbances and was well utilized by the human body. 

OLEO OIL. 

Beef tallow, like other edible fats, consists essentially of olein, 
palmitin, and stearin. In order to utilize most efficiently the enor- 
mous quantities of beef tallow that result from the slaughter of cattle 
in this country yearly, it has been found satisfactory to separate 
the beef tallow into soft (oleo oil) and hard (oleo stearin) fats. The 

1 U. S. Dept. Agr. Bui. 310 (1915), p. 21. 
2 U. S. Dept. Agr. Bui. 507 (1917), p. 18. 



DIGESTIBILITY OF MISCELLANEOUS ANIMAL FATS. 



13 



commercial manufacture of oleo oil and oleo stearin is, in brief, as 
follows : The rough fat from the slaughtered animal is washed with 
warm water, hardened naturally or by immersing in ice water. The 
hardened fat is finely cut, rendered in tin-lined jacketed vessels, and 
allowed to stand for a time in a crystallizing room, the temperature 
of which is carefully regulated, after which it is subjected to 
hydraulic pressure. The soft oleo oil runs out of the press and the 
hard oleo stearin remains in the press. Though they have very ex- 
tensive commercial uses, oleo oil and oleo stearin are little known 
to the housekeeper. 

While both the oleo oil and oleo stearin are used as constituents of 
compounded fats, designed for table and culinary purposes, oleo oil 
is also used as a separated fat by persons who, because of national or 
religious customs, prefer it to other types of animal fats. Oleo oil 
is also used in large quantities in the manufacture of oleomargarin. 

The oleo oil which was studied in the experiments here reported 
was obtained from a dealer in edible fats and was held to be repre- 
sentative of commercial oleo oil. In appearance it was a light yellow 
fat of about the same consistency as butter, solid at ordinary room 
temperature, and without distinctive odor or taste. 

The results which were obtained with oleo oil are included in the 
following tables : 

Data of digestion experiments with oleo oil in a simple mixed diet. 





Weight 
of foods. 


Constituents of foods. 


Experiments, subjects, and diet. 


Water. 


Protein. 


Fat. 


Carbohy- 
drate. 


Ash. 


Experiment No. 805, subject J. F. C: 

Blancmange containing oleo oil 


Grams. 
1, 125. 

377.0 
1,316.0 

310.0 


Grams. 

500.7 

33.9 

1, 143. 6 


Grams. 
19.7 
40.0 
10.5 


Grams. 

146.8 

5.7 

2.6 


Grams. 
449.2 
291.4 
152.7 
310.0 


Grams. 
8.6 


Wheat biscuit 


6.0 


Fruit 


6.6 


Sugar 














Total food consumed 


3, 128. 
88.0 


1, 678. 2 


70.2 
23.8 
46.4 


155.1 

13.3 

141.8 


1,203.3 

43.1 

1, 160. 2 


21.2 


Feces 


7.8 


Am^nnt utilized 




13.4 










Per cent utilized 






66.1 


91.4 


96.4 


63.4 










Experiment No. 806, subject T. G. H.: 

Blancmange containing oleo oil 


1, 482. 

84.0 

1, 468. 

199.0 


659.6 

7.6 

1, 275. 7 


25.9 

8.9 

11.8 


193.4 
1.3 
2.9 


591.8 

64.9 

170.3 

199.0 


11.3 


Wheat biscuit 


1.3 


Fruit 


7.3 


Sugar 














Total food consumed 


3, 233. 
123.0 


1, 942. 9 


46.6 
35.4 
11.2 


197.6 

24.9 

172.7 


1, 026. 

52.3 

973.7 


19.9 


Feces 


10.4 


Amount utilized 




9.5 










Per cent utilized 






24.0 


87.4 


94.9 


47.7 











14 BULLETIN 613, U. S. DEPARTMENT OF AGRICULTURE. 

Data of digestion experiments ivith oleo oil in a simple mixed diet — Continued. 





Weight 
of foods. 


Constituents of foods. 


Experiments, subjects, and diet. 


Water. 


Protein. 


Fat. 


Carbohy- 
drate. 


Ash. 


Experiment No. 807, subject P.K.: 

Blancmange containing oleo oil 


Grams. 

1,201.0 
300.0 
291.0 
293.0 


Grams. 

534.6 

27.0 

252.9 


Grams. 

21.0 

31.8 

2.3 


Grams. 

156.7 

4.5 

.6 


Grams. 

479.6 

231.9 

33.7 

293.0 


Grams. 
9 1 


Wheat biscuit 


4.8 


Fruit 


1 5 


Sugar 














Total food consumed 


2, 085. 
63.0 


814.5 


55.1 
18.2 

36.9 


161.8 

14.7 

147.4 


1, 038. 2 

23.4 

1,013.8 


15 4 


Feces 


6 7 


Amount utilized 




8 7 
















67.0 


90.9 


97.7 


56 5 










Experiment No. 808, subject G. S. M.: 

Blancmange containing oleo oil 


1, 368. 
346.0 

1,350.0 
415.0 


608.9 

31.1 

1, 173. 1 


23.9 
36.7 
10.8 


178.5 
5.2 
2.7 


546.3 
267.5 
156.6 
415.0 


10 4 


Wheat biscuit 


5 5 


Fruit 


6.8 


Sugar 














Total food consumed 


3,479.0 
152.0 


1, 813. 1 


71.4 
42.0 
29.4 


186.4 

15.2 

171.2 


1, 385. 4 

81.5 

1,303.9 


22 7 


Feces 


13 3 


Amount utilized 




9 4 










Per cent utilized 






41.2 


91.8 


94.1 


41 4 










Experiment No. 809, subject D. D. M.: 

Blancmange containing oleo oil 


1, 366. 
623.0 

1,310.0 
414.0 


608.0 

56.1 

1,138.4 


23.9 
66.0 
10.5 


178.3 
9.3 
2.6 


545.4 
481.6 
152.0 
414.0 


10 4 


Wheat biscuit 


10 


Fruit 


6 5 


Sugar 














Total food consumed 


3,713.0 
128.0 


1,802.5 


100.4 
37.3 
63.1 


190.2 

14.2 

176.0 


1, 593. 

65.1 

1, 527. 9 


26 9 


Feces 


11 4 


Amount utilized 




15.5 










Per cent utilized 






62.8 

22.2 

38.8 
9.2 


92.5 

165.4 
5.5 
2.3 


95.9 


57 6 












Experiment No. 810, subject M. L. M.: 

Blancmange containing oleo oil 


1,267.0 
366.0 

1, 152. 
401.0 


563.9 

32.9 

1, 001. 1 


505.9 
282.9 
133.6 
401.0 


9.6 


Wheat biscuit 


5 9 


Fruit 


5 8 


Sugar 














Total food consumed 


3, 186. 
99.0 


1,597.9 


70.2 
33.7 
36.5 


173.2 

14.6 

159.6 


1,323.4 

42.0 

1,281.4 


21 3 


Feces 


8 7 


Amount utilized 




12 6 










Per cent utilized 






52.0 


91.6 


96.8 


59.2 










Experiment No. 811, subject J. C. M.: 

Blancmange containing oleo oil 


1,162.0 
426.0 

1, 243. 
135.0 


517.2 

38.3 

1,080.2 


20.3 

45.2 

9.9 


151.7 
6.4 
2.5 


464.0 
329.3 
144.2 
135.0 


8 8 


Wheat biscuit 


6 8 


Fruit 


6 2 


Sugar 














Total food consumed 


2, 966. 
93.0 


1,635.7 


75.4 
24.3 
51.1 


160.6 
15.2 

145.4 


1, 072. 5 

43.2 

1,029.3 


21 8 


Feces 


10 3 


Amount utilized 




11 5 










Per cent utilized 






67.8 


90.5 


96.0 


52 8 










Experiment No. 812, subject W. O'C: 

Blancmange containing oleo oil 


1,476.0 
191.0 

1, 125. 
467.0 


657.0 

17.2 

977.6 


25.8 

20.2 

9.0 


192.6 
2.9 
2.3 


589.4 
147.6 
130.5 
467.0 


11 2 


Wheat biscuit T 


3 1 


Fruit 


5 6 


Sugar 














Total food consumed 


3, 259. 
119.0 


1, 651. 8 


55.0 
32.1 
22.9 


197.8 
25.0 

172.8 


1, 334. 5 

48.4 

1, 286. 1 


19 9 


Feces 


13 5 


Amount utilized 




6 4 










Per cent utilized 






41.6 


87.4 


96.4 


32 2 










Average food consumed per subject per day. . . 


1, 043. 7 


539.0 


22.7 


59.3 


415.7 


7.0 



DIGESTIBILITY OF MISCELLANEOUS ANIMAL FATS. 15 

Summary of digestion experiments luith olco oil in a simple mixed diet. 





Experiment No. 


Subject. 


Digestibility of entire ration. 


Esti- 
mated 




Protein. 


Fat. 


Carbohy- 
drate. 


Ash. 


digesti- 
bility of 
oleo oil 
alone. 


805 


J. F. C 


Per cent. 
66.1 
24.0 
67.0 
41.2 
62.8 
52.0 
67.8 
41.6 


Per cent. 
91.4 
87.4 
90.9 
91.8 
92.5 
91.6 
90.5 
87.4 


Per cent. 
96.4 
94.9 
97.7 
94.1 
95.9 
96.8 
96.0 
96.4 


Per cent. 
63.4 
47.7 
56.5 
41.4 
57.6 
59.2 
52.8 
32.2 


Per cent. 
96.9 


806 


T. G. H 


93.4 


807 


P. K 


94.6 


808 


G. S. M 


99.9 


809... 


D. D.M 


99.1 


810. . 


M.L. M 


97.1 


811 


J. C. M 


96.0 


812.. 


W. O'C 


97.2 




Average ; 








52.8 


90.4 


96.0 


51.4 


96.8 











The subjects ate on an average 23 grams of protein, 59 grams of 
fat, and 416 grams of carbohydrate daily. The digestibility of these 
food constituents was found to be 52.8 per- cent for protein, 90.4 per 
cent for fat, and 96 per cent for carbohydrate. The estimated di- 
gestibility of oleo oil alone was 96.8 per cent, which is somewhat 
higher than the digestibility (93 per cent) previously reported for 
beef tallow, 1 which contains the oleo stearin as well as the oleo oil. 

The subjects reported no ill effects from the test periods with oleo 
oil. The coefficient of digestibility of oleo oil, 96.8 per cent, as ob- 
tained in the above experiments, is practically identical with the 
reported 2 coefficients of digestibility of the common animal and vege- 
table fats, which, on the average, are 97 per cent. 

OLEO STEARIN. 

Oleo stearin, which is obtained as outlined above, is ordinarily a 
white, odorless, tasteless fat, solid at ordinary room temperature. 
It is quite extensively used in the manufacture of compounded edible 
fats commonly known as lard substitutes and lard compounds, but 
has relatively little if any use in the home as such for culinary 
purposes. 

A supply of oleo stearin sufficient for the purpose of this study was 
obtained from a dealer who was able to supply it in quantity, and it 
was known to be typical of commercial oleo stearin. 

Three experiments were made to determine the digestibility of oleo 
stearin, and the data obtained are tabulated on page 16. 

*U. S. Dept. Agr. Bui. 310 (1915), p. 21. 
2 See list on page 26. 



16 BULLETIN" 613, U. S. DEPARTMENT OF AGRICULTURE. 

Data of digestion experiments with oleo stearin in a simple mixed diet. 





Weight 
of foods. 


Constituents of foods. 


Experiments, subjects, and diet. 


Water. 


Protein. 


Fat. 


Carbohy- 
drate. 


Ash. 


Experiment No. 825, subject J. F. C: 

Blancmange containing oleo stearin 

Wheat biscuit 


Grams. 

1, 164. 
278.0 
856.0 
142.0 


Grams. 

528.3 

25.0 

743.9 


Grams. 

20.4 

29.5 

6.8 


Grams. 

198.6 

4.2 

1.7 


Grams. 

410.9 

214.9 

99.3 

142.0 


Grams. 
5.8 
4.4 


Fruit 


4.3 


Sugar 














Total food consumed 


2,440.0 
153.0 


1,297.2 


56.7 
33.6 
23.1 


204.5 

61.6 

142.9 


867.1 

44.5 

822.6 


14.5 


Feces 


13.3 


Amount utilized 


1.2 










Per cent utilized 






40.7 


69.9 


94.9 


8.3 












Experiment No. 827, subject T. G. H.: 

Blancmange containing oleo stearin 

Wheat biscuit 


1,012.0 

39.0 

617.0 

167.0 


459.3 

3.5 

536.2 


17.7 
4.1 
4.9 


172.7 
0.6 
1.2 


357.2 
30.2 
71.6 

167.0 


5.1 
0.6 


Fruit 


3.1 


Sugar 














Total food consumed 


1, 835. 
92.0 


999.0 


26.7 

17.0 

9.7 


174.5 

36.7 

137.8 


626.0 

31.7 

594.3 


8.8 


Feces 


6.6 


ATnonnt utilized 




2.2 










Per cent utilized 






36.3 


79.0 


94.9 


24.7 










Experiment No. 828, subject F. K.: 

Blancmange containing oleo stearin 

Wheat biscuit 


1,317.0 
467.0 
791.0 
176.0 


597.8 

42.0 

687.4 


23.0 

49.5 

6.3 


224.7 
7.0 
1.6 


464.9 

361.0 

91.8 

176.0 


6.6 
7.5 


Fruit 


3.9 


Sugar 














Total food consumed 


2, 751. 
199.0 


1,327.2 


78.8 
43.8 
35.0 


233.3 

78.4 
154. 9 


1,093.7 

61.7 

1,032.0 


18.0 


Feces 


15.1 


Amount utilized 




2.9 










Per cent utilized 






44.4 


66.4 


94.4 


16.6 










Average food consumed per subject per day. . . 


780.6 


402.6 


18.0 


68.0 


281.8 


4.6 



Summary of digestion experiments with oleo stearin in a simple mixed diet. 





Experiment No. 


Subject. 


Digestibility of entire ration. 


Esti- 
mated 




Protein. 


Fat. 


Carbohy- 
drate. 


Ash. 


digesti- 
bility of 

oleo 
stearin 
alone. 


825 


J. F. C 

T. G. H 


Per cent. 
40.7 
36.3 
44.4 


Per cent. 
69.9 
79.0 
66.4 


Per cent. 
94.9 
94.9 
94.4 


Per cent. 

8.3 

24.7 

16.6 


Per cent. 
76.6 


827 


89.8 


828. . 


F. K 


73.9 




Average 








40.5 


71.8 


94.7 


16.5 


80.1 











On an average the daily diet supplied 18 grams protein, 68 grams 
fat, and 281.8 grams carbohydrate, the energy value being 1,811 
calories. 

Considering the digestibility of the ration as a whole on an average 
the subjects digested 40.5 per cent of the protein, 71.8 per cent of 
the fat, and 94.7 per cent of the carbohydrate. The estimated digesti- 
bility of the oleo stearin alone is 80.1' per cent. The figure, as would 
naturally be expected, is considerably lower than that of oleo oil, 



DIGESTIBILITY OF MISCELLANEOUS ANIMAL FATS. 17 

96.7 per cent, and also lower than 93 per cent, the digestibility of beef 
tallow, which consists of both oleo oil and oleo stearin. 

In their reports of their physical condition during the test period, 
the subjects noted no unusual physiological conditions. 

OX-MARROW FAT. 

It is believed by many people that bone marrow possesses proper- 
ties which make it of particular value for food purposes and of 
especial value in the dietary of invalids and convalescents. That 
there is a scientific basis for such belief is shown by a review of the 
literature. In discussing the value of fat in the diet Friedenwald 
and Ruhr ah x say that bone marrow, which is rich in fat, is used in 
the treatment of tuberculosis and pernicious anemia. The marrow of 
young animals is preferred, and the glycerin extract of bone marrow 
is utilized. Zink 2 states : " Yellow marrow contains chiefly fat which 
consists of olein, palmitin, and stearin, and which differs from the 
fat of the other parts of the body in having a higher acetyl equiv- 
alent." In a study of red marrow Forrest 3 obtained two proteins, 
one a globulin coagulating at 47-50° C, which contained no phos- 
phorus, and a second a nucleo-albumin which was found to contain 
phosphorus in its molecule. Glikin 4 reports that iron occurs regu- 
larly in beef marrow, the marrow of young animals containing larger 
amounts than that of old animals. According to Halliburton 5 the 
most important protein of red marrow " is a nucleo-protein which 
contains 1.6 per cent of phosphorus." In considering the dietary 
value of marrow, however, it must be remembered that it contains a 
large amount of marrow fat and that this, like all other fats, is a 
valuable source of energy in addition to the special therapeutic value 
attributed to it. Marrow is well known as food. Common examples 
are marrow bones, an old-fashioned dish, and marrow balls, which 
are served in soup. 

The preparation of marrow fat is confined very largely to the pack- 
ing houses, where it is obtained from the leg bones of beef animals. 
The process, according to information obtained from the Bureau 
of Animal Industry, is as follows : 

Marrow fat is prepared from long or shank bones, they being first heated in 
water at a temperature of from 160° to 170° Fahrenheit. Both ends of the 
bones are sawed off and the marrow removed by blowing with compressed air. 

1 Diet in Health and Disease. Philadelphia and London : W. B. Saunders Co., 1913, 4. 
ed., p. 144. 

2 Chem. Zenthl., 68 (1897), No. 5, p. 296. 
. 8 Jour. Physiol., 17 (1894-5), p. 175. 
±Ber. Deut. Chem. Gesell., 41 (1908), No. 5, p. 910. 
5 Jour. Physiol., 18 (1895), No. 4, pp. 306-318. 



18 



BULLETIN 613, U. S. DEPARTMENT OF AGRICULTURE. 



It is placed in cans, being processed in the usual manner for processing canned 
meat products. When prepared in this manner it is put out in the trade as 
" ox marrow." 

For the purpose of this study a supply of this fat, packed in Im- 
pound tins labeled " Ox-Marrow Fat," was obtained from commercial 
sources. In appearance it was of a yellow color, solid at room tem- 
perature, and without a characteristic odor. The fat was -melted, 
thoroughly mixed, and a sample analyzed by R. H. Kerr, of the 
Bureau of Animal Industry, was found to have an iodin number 
of 48.48, refractive index of 47°, with a Zeiss butyro-refractometer 
at 40°, and 0.56 per cent of free acid. 

The marrow fat was incorporated in a blancmange and eaten as 
a constituent of the usual simple mixed diet by four subjects. The 
results of the experiments are reported in the following tables : 

Data of digestion experiments with ox-marrotv fat in a simple mixed diet. 





Weight 
of foods. 


Constituents of foods. 


Experiments, subjects, and diet. 


Water. 


Protein. 


Fat. 


Carbohy- 
drate. 


Ash. 


Experiment No. 692, subject P. K.: 

Blancmange containing ox-marrow fat 

Wheat biscuit 


Grams. 

1, 700. 
305.0 
418.0 
136.0 


Grams. 

710.1 

27.4 

363.2 


Grams. 

30.8 

32.3 

3.4 


Grams. 

294.8 

4.6 

0.8 


Grams. 

651.1 

235.8 

48 5 

136.0 


Grams. 

13.2 

4.9 


Fruit 


2.1 


Sugar 










1 




Total food consumed 


2, 559. 
76.0 


1,100.7 


66.5 
21.1 
45.4 


300.2 

26.0 

274.2 


1,071.4 

23.2 

1, 048. 2 


20.2 


Feces 


5.7 


Amount utilized 




14.5 










Per cent utilized 






68.3 


91.3 


97.8 


71.8 










Experiment No. 693, subject J. C M.: 

Blancmange containing ox-marrow fat 

Wheat biscuit 


1,928.0 
371.0 
796.0 
122.0 


805.3 

33.4 

691.7 


34.9 

39.3 

6.4 


334.3 
5.6 
1.6 


738.4 

286.8 

92.3 

122.0 


15.1 
5.9 


Fruit 


4.0 


Sugar 














Total food consumed 


3,217.0 
83.0 


1, 530. 4 


80.6 
24.8 
55.8 


341.5 

22.9 

318.6 


1,239.5 

27.5 

.1,212.0 


25.0 


Feces 


7.8 


Amount utilized 




17.2 










Per cent utilized 






69.2 


93.3 


97.8 


68.8 










Experiment No. 694, subject A. A. R.: 

Blancmange containing ox-marrow fat 

Wheat biscuit 


1,793.0 
118.0 

1,246.0 
122.0 


748.9 

10.6 

1,082.8 


32.5 
12.5 
10.0 


310.9 
1.8 
2.5 


686.7 

91.2 

144.5 

122.0 


14.0 
1.9 


Fruit 


6.2 


Sugar 














Total food consumed 


3,279.0 
108.0 


1,842.3 


55.0 
37.7 
17.3 


315.2 

28.7 

286.5 


1,044.4 

31.9 

1,012.5 


22.1 


Feces 


9.7 


Amount utilized 




12.4 










Per cent utilized 






31.5 


90.9 


96.9 


56.1 










Experiment No. 695, subject W. E. T.: 

Blancmange containing ox-marrow fat 

Wheat biscuit 


588.0 
313.0 
989.0 
138.0 


- 245.6 

28.2 

859.4 


10.6 
33.2 

7.9 


102.0 
4.7 
2.0 


225.2 
241.9 
114.7 
138.0 


4.6 
5.0 


Fruit 


5.0 


Sugar 














Total food consumed 


2,028.0 
56.0 


1,133.2 


51.7 
16.6 
35.1 


108.7 
11.6 
97.1 


719.8 

20.5 

699.3 


14.6 


Feces 


7.3 


Amount utilized 




7.3 










Per cent utilized 






67.9 


89.3 


97.2 


50.0 










Average food consumed per subject per day . 


923.6 


467.2 


21.2 


88.8 


339.6 


6.8 



DIGESTIBILITY OF MISCELLANEOUS ANIMAL FATS. 19 

Summary of digestion experiments with ox-marrow fat in a simple mixed diet. 





Subject. 


Digestibility of entire ration. 


Esti- 
mated 


Experiment Xo. 


Protein. 


Fat. 


Carbohy- 
drate. 


Ash. 


digesti- 
bility of 
ox-mar- 
row fat 
alone. 


692 


P. K 


Per cent. 
68.3 
69.2 
31.5 
67.9 


Per cent. 
91.3 
93.3 
90.9 
89.3 


Per cent. 
97.8 
97.8 
96.9 
97.2 


Per cent. 
71.8 
68.8 
56.1 
50.0 


Per cent. 
93.7 


693.. 


J. C. M 


95.6 


694 . . 


A. A. R 


91.6 


695 


W. E. T 


93.1 








Average 


59.2 


91.2 


97.4 


61.7 


93.5 







Iii the experiments reported above the subjects ate on an average 
21 grams of protein, 89 grams of fat (of which 87 grams were mar- 
row fat), and 310 grams of carbohydrate. This diet furnished ap- 
proximately 2,215 calories of energy daily. It will be noted that in 
experiment No. 695 the subject W. E. T., who did not possess a very* 
vigorous appetite, ate only 109 grams of fat during the three-day 
period. The other subjects averaged 101 grams of fat daily. The 
protein supplied by the diet was 59.2 per cent digested, the fat 
91.2 per cent, and the carbohydrate 97.1 per cent. The figure 91.2 
per cent for the digestibility of the total fat of the diet becomes 93.5 
per cent for the digestibility of marrow fat alone when correction is 
applied for the metabolic products and undigested basal-ration fat 
which occurs in the ether extract of the feces. 

The consumption of 100 grams of marrow fat daily for a period of 
three days or more evidently caused digestive disturbances since 
in experiment Xo. 692, subject P. K. reported : " Health was normal 
when entering on the diet. During the period experienced a slight 
headache and a sickish feeling." In experiment Xo. 693, subject 
J. C. ML reported : " Felt a severe weakness accompanied by cold 
perspiration.'' In experiment Xo. 691, subject A. A. It. reported: 
" Pains in head and abdomen, general feeling of weakness." In ex- 
periment Xo. 695, subject Tv\ E. T. reported: " Health normal at start 
of diet, during diet headache with general weak feeling." 

On the basis of these experiments alone, it would appear that the 
continued consumption of 100 grams of marrow fat daily is likely to 
be attended with physiological disturbances. The results of the ex- 
jieriments indicate, however, that this fat is as completely digested as 
the common animal and vegetable fats. 

OX-TAIL FAT. 

Ox-tail fat is separated and marketed as an edible fat to a small 
extent at least in this country. In reply to an inquiry regarding its 
commercial production, one food-packing concern states : " This fat 



20 



BULLETIN 613, U. S. DEPARTMENT OF AGRICULTURE. 



is not a by-product with us, but is used in the preparation of our ox- 
tail soup. We have absolutely no means of estimating the quantities 
of this fat produced in this country." A second concern reports : "We 
produce considerable quantities ourselves, some of which we use and 
some of which we sell. It is more liquid than other beef fats, con- 
taining less stearin, and for this reason would be better adapted to 
the manufacture of oleo oil. We sell it as an edible fat, and so far 
as we know, it is used with other beef fats as a shortening or for 
other food purposes." 

Even if little of the fat is marketed for food purposes, it is evident 
that it is not uncommonly so used when one recalls that it is a con- 
stituent of freshly made and canned ox -tail soup. 

For the purpose of this study a sufficient quantity of ox-tail fat was 
secured from a concern which did not include the ox-tail fat in 
the ox-tail soup which it packed. In appearance the fat was a 
cream white solid when chilled. At ordinary room temperature the 
fat separated into two layers, about four-fifths being a pale yellow 
solid and about one-fifth a light yellow oil. The fat possessed no 
pronounced odor or flavor. An examination 1 showed it to have the 
following characteristics : Index of refraction at 40° C, 49.0° ; iodin 
number, 56.58; and melting point 37.0° to 36.8°. 

Three subjects assisted in the study of the digestibility of ox-tail fat 
and the data obtained are reported in the tables which follow : 



Data of digestion experiments with ox-tail fat in a simple mixed diet. 





Weight 
of foods. 


Constituents of foods. 


Experiments, subjects, and diet. 


Water. 


Protein. 


Fat. 


Carbohy- 
drate. 


Ash. 


Experiment No. 704, subject P. K. : 

Blancmange containing ox-tail fat 


Grams. 

1,814.0 
302.0 
545.0 
251.0 


Grams. 

824.3 

27.2 

473.6 


Grams. 

35.9 

32.0 

4.4 


Grams. 

227.1 

4.5 

1.1 


Grams. 

711.8 

233.5 

63.2 

251.0 


Grams. 
14.9 


Wheat biscuit 


4.8 


Fruit 


2.7 


Sugar 














Total food consumed 


2, 912. 
58.0 


1, 325. 1 


72.3 

17.8 
54.5 


232.7 

13.7 

219.0 


1, 259. 5 

21.0 

1,238.5 


22.4 


Feces 


5.5 


Amount utilized 




16.9 










Per cent utilized 






75.4 


94.1 


98.3 


75.5 










Experiment No. 705, subject J. C. M.: 

Blancmange containing ox-tail fat 

Wheat biscuit 


2, 004. 
399.0 
825.0 
148.0 


910.6 

35.9 

716.9 


39.7 
42.3 

6.6 


250.9 
6.0 
1.7 


786.4 

308.4 

95.7 

148.0 


16.4 
6.4 


Fruit 


4.1 


Sugar 














Total food consumed 


3, 376. 
86.0 


1, 663. 4 


88.6 
26.0 
62.6 


258.6 

13.0 

245. 6 


1, 338. 5 

38.2 

1,300.3 


26.9 


Feces 


8.8 


Amount utilized 




18.1 










Per cent utilized 






70.7 


95.0 


97.2 


67.3 











1 Analysis submitted by meat inspection laboratories of Bureau of Animal Industry. 



DIGESTIBILITY OF MISCELLANEOUS ANIMAL FATS. 21 

Data of digestion experiments ivith ox-tail fat in a simple mixed diet — Contd. 





Weight 
of foods. 


Constituents of foods. 


Experiments, subjects, and diet. . 


Water. 


Protein. 


Fat. 


Carboh y- 
drate. 


Ash. 


Experiment No. 706, subject A. A. R.: 

Blancmange containing ox-tail fat 


Grams. 
1,537.0 

244.0 
1. 192. 

118. 


Grams. 

698.4 

21.9 

1,035.8 


Grams. 

30.5 

25.9 

9.5 


Grams. 

192.4 

3.7 

2.4 


Grams. 
603.1 
188.6 
138.3 
118.0 


Grams. 
12.6 


Wheat biscuit 


3.9 


Fruit 


6.0 


Sugar 














Total food consumed 


3,091.0 
115.0 


1, 756. 1 


65.9 
14.7 

51.2 


198.5 

20.2 

178.3 


1,048.0 

69.4 

978.6 


22.5 


Feces 


10.7 


Amount utilized 




11.8 










Per cent utilized 






77.7 


89.8 


93.4 


52.4 










Average food consumed per subject per day . . . 


1, 042. 1 


527.2 


25.2 


76.6 


405. 1 


8.0 



Summary of digestion experiments with ox-tail fat in a simple mixed diet. 





Experiment No. 


Subject. 


Digestibility of entire ration. 


Esti- 
mated 




Protein. 


Fat. 


Carbohy- 
drate. 


Ash. 


digesti- 
bility of 
ox-tail 
fat alone. 


704 


P. K 


Per cent. 
75.4 
70.7 

77.7 


Per cent. 
94.1 
95.0 
89. 


Per cent. 
98.3 
97.2 
93.4 


Per cent. 
75.5 
67.3 
52.4 


Per cent. 
96.3 


705 


J. CM 


98.2 


706 


A. A. R 


95.4 




Average 








74.6 


93.0 


96.3 


65.1 


96.6 











The daily diet supplied on an average 25.2 grams protein, 76.6 
grams fat, and 405.1 grams carbohydrate, the energy value being 
2,411 calories. 

The average digestibility of the diet as a whole was found to be 
74.6 per cent for protein, 93 per cent for fat, and 96.3 per cent 
for carbohydrate when 25 grams of protein, 77 grams of fat, and 
405 grams of carbohydrate were eaten daily. The estimated digesti- 
bility of ox-tail fat alone was found to be 96.6 per cent when the 
usual correction was made for the metabolic products and undigested 
basal-ration fat occurring in the ether extract of the feces. 

In reports of their physical condition during the test period, the 
subjects made no reference to any laxative effect resulting from the 
diet, and accordingly it is assumed that the limit of tolerance for 
ox-tail fat is in excess of 84 grams daily, the amount eaten by one 
of the subjects, J. C. M., for the three-day test period. 

In so far as these experiments are concerned, it would appear that 
ox-tail fat, which is quite completely digested and does not produce 
physiological disturbances when eaten in normal amounts, should 



22 BULLETIN 613, IT. S. DEPARTMENT OF AGRICULTURE. 

prove a satisfactory source of energy for the dietary whether eaten 
as a separate fat or as a constituent of ox-tail soup. 

It has often been noted that fats from the different parts of the 
body possess different chemical and physical characteristics. In this 
connection it is interesting to note the values obtained for the di- 
gestibility of the different beef fats reported in this and other bulle- 
tins of this series which were for beef tallow 1 93 per cent, beef- 
brisket fat 2 97.4 per cent, hard-palate fat 93.7 per cent, ox-marrow 
fat 93.5 per cent, and ox-tail fat 96.6 per cent. These values would, 
of course, be more directly comparable had it been possible to secure 
a sufficient supply of these different fats from a single animal. 

TURTLE FAT. 

The flesh of the green turtle (Chelonia my das), a sea turtle which 
lives mostly in deep water and feeds largely upon vegetable matter, 
is used considerably for food. The portion of the flesh known as 
" calif ash " adhering to the upper shell, has a high oil content, is 
of a dull greenish color, and is very highly prized, being used 
in the preparation of turtle soup. According to Ditmar 3 the name 
green turtle is due to the greenish color of the oil. 

The experiments which follow were conducted to secure data con- 
cerning the extent to which green-turtle fat is utilized by the body. 
Through the courtesy of R. L. Coker of the United States Bureau of 
Fisheries, several cans of so-called turtle fat were secured from a 
Florida dealer. On opening, the cans were found to contain a dull 
greenish substance, the " califash," resembling liver in appearance, 
and surrounded by small quantities of a yellow oil which had sepa- 
rated from it. For the sake of uniformity with other experiments, 
the canned turtle fat was rendered and fed in the same way as 
other fats studied. In order to secure as much of the oil as possible, 
the mass was passed through an ordinary household meat cutter and 
was rendered by heating in a double boiler. The resulting oil was 
of a yellow color without any noticeable odor. 

Four three-day digestion tests were made of green-turtle fat and 
the results which were obtained are reported in the tables which 
follow\ 

!U. S. Dept. Agr. Bui. 310 (1915), p. 21. 
2 U. S. Dept. Agr. Bui. 507 (1917), p. 18. 
s Reptiles of the World. New York : Sturgis and Walton, p. 14. 



DIGESTIBILITY OF MISCELLANEOUS ANIMAL FATS. 23 

Data of digestion experiments with green-turtle fat in a simple mixed diet. 





Weight 
of foods. 


Constituents of foods. 


Experiments, subjects, and diet. 


Water. 


Protein. 


Fat. 


Carbohy- 
drate. 


Ash. 


Experiment No. 681, subject A. F.: 

Blancmange containing green-turtle fat 

Wheat biscuit 


Grams. 

1,933.0 
378.0 
657.0 
227.0 


Grams. 

890.0 

34.0 

570.9 


Grams. 

34.0 

40.1 

5.3 


Grams. 

174.2 

5.7 

1.3 


Grams. 

821.7 

292.2 

76.2 

227.0 


Grams. 

13.1 

6.0 


Fruit. . 


3.3 


Sugar 














Total food consumed 


3, 195. 
73.0 


1,494.9 


79.4 
21.4 
58.0 


181.2 

10.0 

171.2 


1,417.1 

32.4 

1,384.7 


22.4 


Feces ... 


9.2 






13.2 
















73.0 


94.5 


97.7 


58.9 










Experiment No. 682, subject P. K.: 

Blancmange containing green- turtle fat — 
"Wheat biscuit 


1,703.0 
338.0 
368.0 
164.0 


784.1 

30.4 

319.8 


30.0 

35.8 

3.0 


153.4 
5.1 
0.7 


723.9 
261.3 

42.7 
164.0 


11.6 
5.4 


Fruit '. 


1.8 


Sugar 














Total food consumed 


2, 573. 
' 79.0 


1, 134. 3 


68.8 
26.3 
42.5 


159.2 

11.6 

147.6 


1,191.9 

34.3 

1,157.6 


18.8 


Feces 


6.8 






12.0 










Per cent utilized 






61.8 


92.7 


97.1 


63.8 










Experiment No. 683, subject J. C. M.: 

Blancmange containing green-turtle fat 

Wheat biscuit 


1,377.0 
321.0 
780.0 
143.0 


634.0 

28.9 

677.8 


24.2 

34.0 

6.2 


124.1 

4.8 
1.6 


585.4 

248.1 

90.5 

143.0 


9.3 
5.2 


Fruit 


3.9 


Sugar 














Total food consumed 


2,621.0 
105.0 


1,340.7 


64.4 
29.7 
34.7 


130.5 

7.5 

123.0 


1,067.0 

59.9 

1,007.1 


18.4 


Feces 


7.9 


Amount utilized 




10.5 










Per cent utilized 






53.9 


94.2 


94.4 


57.1 








Experiment No. 684, subject A. A. R.: 

Blancmange containing green-turtle fat 

Wheat biscuit 


1, 180. 
159.0 

1,139.0 
396.0 


543.3 

14.3 

989.8 


20.8 

16.9 

9.1 


106.3 
2.4 
2.3 


501.6 
122.9 
132.1 
396.0 


8.0 
2.5 


Fruit 


5.7 


Sugar 














Total food consumed 


2,874.0 
76.0 


1,547.4 


46.8 
27.3 
19.5 


111.0 

9.1 

101.9 


1,152.6 

32.4 

1, 120. 2 


16.2 


Feces 


7.2 


Amount utilized 




9.0 










Per cent utilized 




r 


41.7 


91.8 


97.2 


55.6 










Average food consumed per subject per day . . . 


938.5 


459.8 


21.6 


48.5 


402.4 


6.3 



Summary of digestion experiments icith green-turtle fat in a simple mixed diet. 





Experiment No. 


Subject. 


Digestibility of entire ration. 


Esti- 
mated 




Protein. 


Fat. 


Carbohy- 
drate. 


Ash. 


digesti- 
bility of 

green- 
turtle fat 

alone. 


681 


A. F 


Per cent. 
73.0 
61.8 
53.9 
41.7 


Per cent. 
94.5 
92.7 
94.2 
91.8 


Per cent. 
97.7 
97.1 
94.4 
97.2 


Per cent. 
58.9 
63.8 
57.1 
55.6 


Per cent. 
98.3 


682 


P. K 


97.5 


683 


J. CM 


100.0 


684 


A. A. R 


98.4 




Average 








57.6 


93.3 


96.6 


58.9 


98.6 















24 BULLETIN 613, U. S. DEPARTMENT OF AGRICULTURE. 

On an average the four subjects who assisted in the study of the 
digestibility of turtle fat ate 22 grams of protein, 49 grams of fat, 
and 402 grams of carbohydrate daily. The digestibility of the diet 
as a whole was found to be, for protein 57.6 per cent, for fat, 93.3 
per cent, and for carbohydrate, 96.6 per cent. When allowance is 
made for metabolic products and undigested fat resulting from the 
basal ration, the figure, 93.3 per cent, for the digestibility of the total 
fat of the diet, becomes 98.6 per cent for the digestibility of turtle 
fat alone. In reports of their physical condition the subjects made 
no reference to any laxative effect or other digestive disturbance 
resulting from the diet. Accordingly, it may be assumed that green- 
turtle fat taken in quantities not exceeding 50 grams daily is well 
tolerated and very completely assimilated by the body. 

SUMMARY. 

As a group the fats which are considered in the present paper are 
not extensively used in the home as separate fats, but all are included 
to a greater or less extent in the American dietary. Two of them, 
oleo oil and oleo stearin, find large commercial uses in the manu- 
facture of fats for domestic consumption, oleo oil being used in the 
manufacture of oleomargarin and oleo stearin in the manufacture 
of shortening fats. Since little, if any, information was available 
regarding the extent to which they are utilized by the human body, 
their coefficients of digestibility were determined and found to be 
98.4 per cent for goat's butter, 95.3 per cent for kid fat, 93.7 per 
cent for hard-palate fat, 93.9 per cent for horse fat, 96.8 per cent for 
oleo oil, 80.1 per cent for oleo stearin, 93.5 per cent for ox-marrow fat, 

96.6 per cent for ox-tail fat, and 98.6 per cent for turtle fat. 

The studies of the digestibility of fats here reported include four 
experiments with goat's butter, three experiments with kid fat, three 
experiments with hard-palate fat, three experiments with horse fat, 
eight experiments with oleo oil, three experiments with oleo stearin, 
four experiments with ox-marrow fat, three experiments with ox-tail 
fat, and four experiments with green-turtle fat. 

The subjects ate per day on an average 42.8 grams of goat's butter, 

59.7 grams of kid fat, 87.7 grams of hard-palate fat, 62.9 grams of 
horse fat, 56.8 grams of oleo oil, 66.2 grams of oleo stearin, 86.8 grams 
of ox-marrow fat, 74.5 grams of ox-tail fat, and 46.5 grams of turtle 
fat. 

In the reports of their physical condition during the test periods, 
the subjects did not note any physiological disturbances except in 
the case of ox-marrow fat, which seemed to have a slight laxative 
effect. No evidence was secured as to whether this condition resulted 



DIGESTIBILITY OF MISCELLANEOUS ANIMAL FATS. 25 

from the nature of the fat or from the fairly large amount ingested 
daily. 

The protein and carbohydrate eaten during the test periods with 
the fats studied in these experiments were derived from the same 
foods as in the experiments reported in previous bulletins. The 
coefficients of digestibility for total protein were 72 per cent in the 
goat's butter tests, 88 per cent in the kid-fat tests, 50.9 per cent in 
the hard-palate fat tests, 60 per cent in the horse-fat tests, 52.8 per 
cent in the oleo-oil tests, 40.5 per cent in the oleo-stearin tests, 59 
per cent in the ox-marrow fat tests, 75 per cent in the ox-tail fat 
tests, and 58 per cent in the turtle-fat tests. The coefficients of di- 
gestibility for total carbohydrate were 97.3 per cent in the goat's 
butter tests, 95 per cent in the kid-fat tests, 97.6 per cent in the hard- 
palate fat tests, 96 per cent in the horse-fat tests, 96.0 per cent 
in the oleo-oil tests, 94.7 per cent in the oleo-stearin tests, 97 per 
cent in the ox-marrow fat tests, 96 per cent in the ox-tail fat tests, 
and 97 per cent in the turtle-fat tests. The above coefficients of 
digestibility of protein and carbohydrate supplied b} T the diet as a 
whole indicate that the fats under consideration did not decrease the 
assimilation of these constituents. 

On the basis of the experiments here reported it is evident that 
goat's butter, kid fat, hard-palate fat, horse fat, oleo oil, oleo stearin, 
ox-marrow fat, ox-tail fat, and turtle fat when eaten in amounts 
equivalent to the amount of butter eaten in the normal dietary are 
well assimilated, and judged by this and what is known of their use 
as food fats, should prove wholesome sources of fat for human con- 
sumption. 



PUBLICATIONS OF U. S DEPARTMENT OF AGRICULTURE 
RELATIVE TO FOOD AND NUTRITION. 

AVAILABLE FOR FREE DISTRIBUTION BY THE DEPARTMENT. 

Meats: Composition and Cooking. By Chas. D. Woods. Pp. 31, figs. 4. 1904. 
(Farmers' Bulletin 34.) 

The Use of Milk as Food. By R. D. Milner. Pp. 44. 1911. (Farmers' Bulle- 
tin 363.) 

Care of Food in the Home. By Mrs., Mary Hinman Abel. Pp. 46, figs. 2. 1910. 
(Farmers' Bulletin 375.) 

Economical Use of Meat in the Home. By C. F. Langworthy and Caroline L. 
Hunt. Pp. 30. 1910. (Farmers' Bulletin 391.) 

Cheese and Its Economical Uses in the Diet. By C. F., Langworthy and Caro- 
line L. Hunt. Pp. 40. 1912. (Farmers' Bulletin 487.) 

Mutton and Its Value in the Diet. By C. F. Langworthy and Caroline L. Hunt. 
Pp. 32, figs. 2. 1913. (Farmers' Bulletin 526.) 

The Detection of Phytosterol in Mixtures of Animal and Vegetable Fats. By 
R. H. Kerr. Pp. 4. 1913. (Bureau of Animal Industry Circular 212.) 

Some American Vegetable Food Oils, Their Sources and Methods of Production. 
By H. S. Bailey. (Yearbook Separate 691.) 

FOR SALE BY THE SUPERINTENDENT OF DOCUMENTS, GOVERNMENT PRINTING 

OFFICE, WASHINGTON, D. C. 

Studies on the Influence of Cooking upon the Nutritive Value of Meats at 
the University of Illinois, 1903-4. By H. S. Grindley, Sc. D., and A. D. Em- 
mett, A.M. Pp. 230, tables 136. 1905. (Office of Experiment Stations Bul- 
letin 162.) Price, 20 cents. 
> Studies of the Effect of Different Methods of Cooking upon the Thoroughness and 
Ease of Digestion of Meats at the University of Illinois. By H. S. Grindley, 
Sc. D., Timothy Mojonnier, M. S., and Horace C. Porter," Ph. D. Pp. 100, tables 
38. 1907. (Office of Experiment Stations Bulletin 193.) Price, 15 cents. 

Digestibility of Some Animal Fats. By C. F. Langworthy and A. D. Holmes. 
Pp. 23. 1915. (Department Bulletin 310.) Price, 5 cents. 

Digestibility of Very Young Veal. By C. F. Langworthy and A. D. Holmes. Pp. 
577-588. 1916. (Journal of Agricultural Research, 6 (1916), No. 16.) Price, 
5 cents. 

Digestibility of Hard Palates of Cattle. By C., F. Langworthy and A. D. 
Holmes. Pp. 641-648. 1916. (Journal of Agricultural Research, 6 (1916), 
No. 17.) Price, 5 cents. 

Fats and Their Economical Use in the Home. By A. D. Holmes and H. L. 
Lang. Pp. 26. 1916. (Department Bulletin 469.) Price, 5 cents. 

Studies on the Digestibility of the Grain Sorghums. By C. F. Langworthy and 
A. D. Holmes. Pp. 30. 1916. (Department Bulletin 470.) Price, 5 cents. 

Digestibility of Some Vegetable Fats. By C. F. Langworthy and A. D. Holmes. 
Pp. 20. 1917. (Department Bulletin 505.) Price, 5 cents. 
26 



BULLETIN 613, U. S. DEPARTMENT OF AGRICULTURE. 27 

Studies on the Digestibility of Some Animal Fats. By C. F. Langworthy and 
A. D. Holmes. Pp. 20. 1917. (Department Bulletin 507.) Price, 5 cents. 

Experiments in the Determination of the Digestibility of Millets. By C. F. 
Langworthy and A. D. Holmes. Pp. 11. 1917. (Department Bulletin 525.) 
Price, 5 cents.. 

Digestibility of Dasheen. By C. F. Langworthy and A. D. Holmes. Pp. 12. 
1917. (Department Bulletin 612.) Price, 5 cents. 

Studies on the Digestibility of Some Nut Oils. By A. D. Holmes. Pp. 19. 

"l918. (Department Bulletin 630.) Price, 5 cents. 

Experiments on the Digestibility of Fish. By A. D. Holmes. Pp. 15. 1918. 
(Department Bulletin 649.) Price, 5 cents. 

Digestibility of Some Seed Oils. By A. D. Holmes. Pp. 20. 1918. (Depart- 
ment Bulletin 687.) Price, 5 cents. 

Digestibility of Protein Supplied by Soy-Bean and Peanut Press-Cake Flours. 
By Arthur D. Holmes. Pp. 28. 1918. (Department Bulletin 717.) Price, 
5 cents. 



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